6.0 Electric field

  Electrostatics

Electric field due to a point charge is the space surrounding it, within which an electric force can be experienced by any other charge.

It is represented by $E$.

Consider a positive charge $Q$ is placed at any point in an electric field and it experiences a force $F$, then the electric field is defined as,
$$E = \frac{F}{Q}$$

Note:

• The magnitude of $E$ is the force per unit charge and its direction is that of $F$ (i.e., when the force acts on a positive charge)
  
  
• The direction of $E$ is opposite to that of $F$ when the force acts on a negative charge.
  
  
• The electric field is a vector quantity. Mathematically it is expressed as, $$\overrightarrow E = \frac{{\overrightarrow F }}{Q}$$
  
  
• SI unit of an electric field is $NC^{-1}$. Its dimensional formula is $\left[ {ML{T^{ - 3}}{A^{ - 1}}} \right]$.